Maximum Voltage. PV modules string.

[Solar Apprentice]

Hi, people.

I've a little issue and I'm not sure how to solve it.
There's an installation in which there were strings of 16 PV modules in which the modules have suffered from a huge overheating.
The electrical parameters of the module are: Voc=38.34 V; Isc=8.77 A; Vmp=30.72 V; Imp=8.47 A. The maximum system voltage is 1000 V.
The installation gets high quantities of irradiation.

How can I calculate how many modules could be in a string? Is it 1000/38.34=26? Not sure.
Is this a problem related to the design of the installation?

I'd appreciate any response.

Thanks in advance.

 

[DJSmiley]

1000/38.4 is about right, assuming the ambient temp is 25 degrees (thats the environment temp the voltage is measured at)

Lower temps = higher voltage. You have to take the temp coefficient into account as well. Always assume the lowest temperature which the panels will be exposed to, and calculate from there. Depending on the panels coefficient and the temp in your area you probably can expect 45-50V tops for each panel.

Still, 16 panels are most likely to be within the 1000V range.

However, that high voltage is something which isn't very common. Your wires and breakers have to be able to handle it. Many stuff is 450-600V range usually. Insulation might be insufficient for higher voltages!